Treatment of Tree Wounds.

Valuable trees that have been wounded or mutilated are often sacrificed for lack of the discreet surgery which would repair the injury they have suffered; and Professor C. A. Sargent, of the Bussey Institution, has done good service to farmers, fruit-raisers, and landscape-gardeners, by translating from the French the following practical hints, which we give with slight abridgment:

Bark once injured or loosened can never attach itself again to the trunk; and whenever wounds, abrasures, or sections of loose bark exist on the trunk of a tree, the damaged part should be cut away cleanly, as far as the injury extends. Careful persons have been known to nail to a tree a piece of loosened bark, in hope of inducing it to grow again, or at least of retaining on the young wood its natural covering. Unfortunately the result produced by this operation is exactly opposite to that intended. The decaying wood and bark attract thousands of insects, which find here safe shelter and abundant food, and, increasing rapidly, hasten the death of the tree. In such cases, instead of refastening the loosened bark to the tree, it should be entirely cut away, care being taken to give the cut a regular outline, especially on the lower side; for if a portion of the bark, even if adhering to the wood, is left without direct communication with the leaves, it must die and decay. A coating of coal-tar should be applied to such wounds.

Loosened Bark.—It is necessary to frequently examine the lower portions of the trunk, especially of trees beginning to grow old; for here is often found the cause of death in many trees, in large sheets of bark entirely separated from the trunk. This condition of things, which often can not be detected, except by the hollow sound produced by striking the trunk with the back of the iron pruning-knife, arrests the circulation of sap, while the cavity between the bark and the wood furnishes a safe retreat for a multitude of insects, which hasten the destruction of the tree. The dead bark should be entirely removed, even should it be necessary, in so doing, to make large wounds. Cases of this nature require the treatment recommended for the last class.

Cavities in the Trunk.—Very often, when a tree has been long neglected, the trunk is seriously injured by cavities caused by the decay of dead or broken branches. It is not claimed that pruning can remove defects of this nature; it can with proper application, however, arrest the progress of the evil. The edge of the cavity should be cut smooth and even; and all decomposed matter, or growth of new bark formed in the interior, should be carefully removed. A coating of coal-tar should be applied to the surface of the cavity, and the mouth plugged with a piece of well-seasoned oak securely driven into the place. The end of the plug should then be carefully pared smooth and covered with coal-tar, precisely as if the stump of a branch were under treatment. If the cavity is too large to be closed in this manner, a piece of thoroughly seasoned oak board, carefully fitted to it, may be securely nailed into the opening, and then covered with coal-tar. It is often advisable to guard against the attacks of insects by nailing a piece of zinc or other metal over the board in such a way that the growth of the new wood will in time completely cover it.

Coal-tar, a waste product of gas-works, can be applied with an ordinary painter's brush, and may be used cold, except in very cold weather, when it should be slightly warmed before application. Coal-tar has remarkable preservative properties, and may be used with equal advantage on living and dead wood. A single application, without penetrating deeper than ordinary paint, forms an impervious coating to the wood-cells, which would, without such covering, under external influences, soon become channels of decay. This simple application then produces a sort of instantaneous cauterization, and preserves from decay wounds caused either in pruning or by accident. The odor of coal-tar drives away insects, or prevents them, by complete adherence to the wood, from injuring it. After long and expensive experiments, the director of the parks of the city of Paris finally, in 1863, adopted coal-tar, in preference to other preparations used, for covering tree wounds. In the case of stone fruit trees it should, however, be used with considerable caution, especially on plum trees. It should not be allowed to needlessly run down the trunk; and it is well to remember, that the more active a remedy is the greater should be the care in its application. The practice of leaving a short stump to an amputated branch, adopted by some to prevent the loss of sap, although less objectionable in the case of coniferous trees than in that of others, should never be adopted. Such stumps must be cut again the following year close to the trunk, or cushions of wood will form about their base, covering the trunk with protuberances. These greatly injure the appearance and value of the tree, and necessitate, should it be found desirable, the removal, later on, of such excrescences, causing wounds two or three times as large as an original cut close to the trunk would have made.